FISHES, 
i 
commonly overlapping, By maceration in 
water, scales exhibit a series of laminae, the 
smallest in size having been the first produced ; 
they resemble a cone, the apex of which is out- 
wards, the smallest being in the centre ; hence 
SCALES OP PISHES. 
the appearance of numerous concentric lines, all 
of the same shape, which mark the growth.”’^’ 
Along each side, in most fishes, may be ob- 
served a line, known as the lateral line^ formed 
by scales of peculiar form. They are commonly 
more bony than the other scales, and are pierced 
by a tubular orifice for the escape of a mucous 
secretion, which is poured out from glands be- 
neath, and thus flows over the body for the 
double purpose of protecting the skin from the 
macerating influence of the surrounding water, 
and of diminishing friction in swimming. 
The organs of motion in this Class are the 
fins. They generally take the form of a delicate 
* Yarrell, British FislieSj Introd.xii. 
